(a) Technical Field of the Invention
The present invention is related to an improved 3D air-pumping shoe, and more particularly to one that has respectively provided a first air unit and a second air unit in the front and the rear sections of the outsole of the shoe to allow air passage into the shoe or expel hotter air of the shoe into the atmosphere.
(b) Description of the Prior Art
Whereas one usually gets uncomfortable after wearing a pair of shoes for a long time due to the heat accumulated inside the shoes, air unit containing an air chamber is provided to the outsole to produce air-pumping effects by keeping compressing the air chamber while one walks or runs so to expel the hot air out of the shoes into the ambient.
As taught by an application titled “3D Multi-purpose Air-pumping Shoe” filed by the applicant of the present invention, a shoe has in its outsole provided with multiple recessed air chambers and a primary air chamber connected through one another; multiple air ducts are cut on the peripheral side walls surrounding each air chamber so to connect through the air current flowing between any two given air chambers. A mid sole disposed with multiple ventilation outlets directly in symmetric to those provided on a cushion is provided over the outsole to such extent allowing the projection of those multiple ventilation outlets fall at where over the air chambers. Multiple beads protrude from the top of the cushion and the cushion is provided with multiple through outlets while multiple groups of protrusions extend downward from the bottom, and is paved over the mid sole. A compression point to pump the air is form beneath the projection of each protruded bead so to pump the air on each step into the shoes and pass through those ventilation outlets, air chambers and air ducts to achieve ventilation vertically and laterally while expelling the hot air in the shoe to the ambient for creating 3D ventilation results and maintaining refresh and comfortable wearing of the shoe while massaging one's foot. However, the prior art described above though achieving the ventilation purpose for the show is found with the following flaws. Firstly, the outsole must be molded with air chambers and air ducts connecting through one another resulting in very expensive in the development of the mold for the outsole to increase the production cost. Secondly, the design of the air chambers must be changed whenever the shape of the outsole changes to waive the original design to render more problems to the production of the shoe.